diff --git a/Gemfile b/Gemfile
index 3680aef..28a0512 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ end
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
 gem 'rails', '~> 5.1.7'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index e95dd6d..771161a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -160,7 +160,8 @@ GEM
     polyamorous (2.3.0)
       activerecord (>= 5.0)
     public_suffix (4.0.4)
-    puma (3.12.4)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     pundit (2.1.0)
       activesupport (>= 3.0.0)
     rack (2.2.2)
@@ -283,7 +284,7 @@ DEPENDENCIES
   jbuilder (~> 2.5)
   listen (>= 3.0.5, < 3.2)
   pg (= 1.1.4)
-  puma (~> 3.7)
+  puma (~> 4.3)
   pundit
   rails (~> 5.1.7)
   sass-rails (~> 5.0)